| Author | Message | ||
     Artur |
Hi there! I'm preparing myself for the replacement of the primary gearing on my XB12. I got the primary gearing from XB9, which has 34 teeth (instead of 38). This change will result in the acceleration, but the top speed will go down. The primary gearing ratio changes by about 10%. But to do that I need to resolve one strange problem: I've got no f***ing clue what hex wrench should I use for the primary cover bolts. I tried metric: 4mm is too small, 5mm too big. I bought a box of inch hex keys and none of them is good: 1/8" too small, 3/16 too big. I'm puzzled...  | ||
| Damnut |
They are NOT metric screws holding the primary in place. Off the top of my head I think it is a 5/32. | ||
| Echoseven |
GOOD QUESTION! Also make sure you have a sizeable torque wrench, it takes about 240 ft lbs. on the primary gear nut. Good luck and BUMP! | ||
| Hogs |
Check your tool kit... Sorry was thinking of something else..Brain Fart  (Message edited by hogs on April 25, 2008) | ||
| Artur |
It's neither 5/32  5/32 is less than 4mm and it's too small... that hex is between 4mm and 5mm, so must be between 5/32 and 3/16. | ||
| Artur |
GOOD QUESTION! Also make sure you have a sizeable torque wrench, it takes about 240 ft lbs. on the primary gear nut. Good luck and BUMP! I'm talking about the hex socket size. I have a torque wrench, bout don't have the right hex extension. Got no clue what size is that hex bolt.}} (Message edited by Artur on April 25, 2008) | ||
| Werewulf |
im waiting for someone to do this mod to an 08... im told they are different from previous years and i would like to find out what the difference in the gear is, as its got an 08 part number.. | ||
| Jos51700 |
Are you using quality Allen keys, or Chinese Junk. (Lots of times, they'll make only one key size, and label it to the closest metric and standard size, so it fits both poorly). They should be 3/16. | ||
| M1combat |
It's 3/16" You'll need to remove the clutch as well so you need both large sockets. I think it's 1" and 1-1/8". You'll need a tool to lock the primary as well. A flat piece of metal about 4.25" long should work. I don't recommend using the brakes as then you're putting a LOT of torque through your transmission. | ||
| Sgthigg |
Holy crap, You HAVE to remove the clutch as well to do the gear swap?? I didnt realize that. Glad I know now. How about to just tighten the nut to the new torque standard? | ||
| Artur |
The Workshop Manual doesn't say anything about removing the clutch. You just have to loosen and unhook the clutch cable. I have 3/16" hex sockets and they don't fit in the primary cover bolts... | ||
| Bombardier |
Why do you ned to remove the clutch as well M1? I have had a close look at mine and it would seem to be as simple as removing the primary drive gear and replacing it with the smaller 9 gear and chain. If you back the adjuster right out it should give you enough room Yes? | ||
| New12r |
I have done this a couple times now and never had to remove the clutch. | ||
| Damnut |
3/16  | ||
| Wantxbr |
Damnut is correct its a 3/16 allen to remove the 1/4-20 primary cover bolts. Don't forget the T-27 torx bit as well. (Message edited by wantxbr on April 26, 2008) | ||
| Point_doc |
While you have your primary cover off, you might consider replacing the 5 inspection plate threaded holes with heli-coils. I also installed bolt liners (97305A110) from McMaster-Carr into the backside of my primary cover. All cast metal products should have these. (Message edited by point_doc on April 27, 2008) | ||
| Luxor |
I've just finished a major primary service on my 9 and you must remove the clutch to get the chain off. It is EASY to remove the clutch though, you will need a pair of reverse-able lock ring pliers. Just remove the throw-out bearing(the bearing with the threaded shaft used to adjust the clutch)by removing the lock ring, once out the nut(1-3/16) that holds the whole clutch bell is easily accessible. The clutch will come out as one unit, no need to disassemble the clutch. Only took me 20 minutes to do the chain swap minus the time to put the primary cover back on. As stated above 3/16 allen for the 13 primary bolts, 80 INCH LBS is the torque spec. There is also a torque sequence that should be followed. You should also use a brand NEW primary gear nut. And it needs to be torqued between 240-260 FT LBS. | ||
| Artur |
thanks guys! I have to get some good set of inch hex bits. the one I have is some crap: the 3/16 from, my set is to big for the primary cover bolts... | ||
| Spacecapsule1 |
Paint_Doc, explain your reasoning for this please. I would like to know.... | ||
| Birdy |
Jason, I think is reasoning is that cast Alu isn't very good at holding threads. By using an heli-coil or threaded insert you have something a bit harder to bite on. Where I work we use a ton of Pen-Nut inserts rather than try and tap into thin metal. | ||
| Point_doc |
Spacecapsule: 1-Heli-coil; because it is aluminum threads with steel bolts. These inspection covers will have frequent visits and one time they will strip, all aluminum threads with steel bolts will. If I had the time I would Heli-coil all of my aluminum threads. I also did my shifter bolt. 2-Bolt Liners; all cast metals (aluminum or steel) should have these installed. All cast metals have a very loosely arranged atom structure and are structurally weak. Thus we have forged cast to try to alleviate some of the problems that are inherent with cast metals. When you remove the cover and inspect the backside of the bolt hole, you will notice that the front of the hole starts out slightly larger that the .25 bolt to accommodate it. But the back side is HUGE, not sure the size because I didn’t measure it but I would bet it’s around 0.40”. The shape of the bolt hole is conical (because a casting part needs to have a taper to release) not cylindrical!! I discovered this when trying to resolve a problem that my bike developed. I reversed my shifting pattern to GP style (1up/4down) pattern. In a short period of time like two hours of the ride my shifter would not return back to the origin. I had to manually return the lever to get the next gear. I replaced the shifter assembly and still had the problem. Replaced the brass bushing and still had the problem. Finally, I gave it some thought and started to loosen one bolt at a time around the primary case and to my surprise a pop sound went off. My primary case was shifting because of the heavy (positive shift) force applied from using the leg to shift vs. the ankle/foot and caused the case to interfere (bind) the shifter shaft. And if you remove the cover and inspect, you will notice that the two locating pin holes in the case are SLOPPY. So, I installed these bolt liners to assist the locating pins in minimizing lateral shifting. Changed the torque pattern to start in an “X” pattern around the shifter shaft. After completing the torque pattern (this technique is old school for aluminum bolts) I took a hand held impact driver and set the bolts once. Hope this is helpful... (Message edited by point_doc on May 05, 2008) | ||
| Jos51700 |
Don't forget, clutch hub nut is LH thread. | ||
| Jlnance |
paint_doc - What is a bolt liner? | ||
| Spacecapsule1 |
Thanks for the info. If you install heli-coils, do you use the same bolts? I don't know anything about them.... do they just thread into the existing hole, like a liner? | ||
| Point_doc |
Heli-coils: You will reuse your current bolts. Also because the bolt holes are "blind", you will want to remove (grind) the point off of the drill so that you do not drill thru the case. Just take the drill bit to the grinder and remove 50% or more of the tip. So now the drill bit will only cut on the outer part of the flute. 5401-4 1/4-20 MASTER HELICOIL THREAD REPAIR KIT http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=505-6422&PMPXNO=1640815 Here is the web page link for the bolt liner. http://www.mcmaster.com/ Spacers and Standoffs This product matches all of your selections. Part Number: 97305A110 $12.68 per Pack of 25 Enjoy, John (Message edited by point_doc on May 01, 2008) | ||
| Gearhead |
Why not keep your 12 gearing and buy an aluminum primary gear and aluminum clutch basket for a 12. Yes, it's more expensive than the 9 conversion but It will pick up the rpm quicker since you'll be shaving 6.5lbs of rotating mass without loosing top end. | ||
| Hogs |
GEarHEad, Who did you say sells these alum. gear for the 12`s? | ||
| Gearhead |
These pieces are made by Evolution Industries and sold through BadWeb sponsor, Revolution Performance. http://www.revperf.com/Products/drivetrain.html Evolution also manufactures an aluminum transmission front belt pulley. The stock piece weighs right at 3lbs, the aluminum one weighs 15oz! | ||
| Hogs |
GEarHEad, YEah I had thought that I emailed them a week or so ago, and their reply was No they did not, not enough demand for them?? | ||
| Gearhead |
If that's the case, contact Evolution Industries directly at (909) 594-7969, ask for Gary. |
